JPS6230935B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling system for a vehicle such as a bus.

A bus cooling system is generally driven by an underfloor sub-engine in addition to the bus's running engine. Typical examples of the arrangement of such a bus cooling device are those described in Japanese Utility Model Application Publication No. 50-2049 and Japanese Utility Model Application Publication No. 51-66945.

In the bus cooling system described in Utility Model Application Publication No. 50-2049, a dedicated sub-engine and compressor are placed in the center of a common frame under the floor, and a radiator, condenser, and blower are placed on one side of the frame with respect to the longitudinal centerline of the vehicle body. Similarly, an evaporator and a blower are arranged on the other side of the frame, and these are arranged and attached in a direction perpendicular to the longitudinal direction of the vehicle body. In this configuration, the heavy sub-engine is located in the center of the vehicle body, so the weight balance in the left-right direction is good, but the height of the sub-engine is large, making it difficult to install, especially on buses with a low floor in the center aisle of the vehicle body. However, there are also drawbacks such as the fact that it cannot be mounted on a bus that has a chassis frame in the center of the vehicle body.

On the other hand, in the bus cooling system described in the above-mentioned Japanese Utility Model Publication No. 51-66945, the sub-engine, compressor, condenser, and radiator are arranged on one end of the same frame under the floor in the direction perpendicular to the longitudinal center line of the vehicle body. However, since the evaporator and the blower are arranged on the other end side of the same frame, the cooling system can be installed even on the aforementioned bus with a low floor in the center aisle of the vehicle body. However, by driving the blower at the other end with the sub-engine at one end, the propeller shaft is installed across the lower part of the bus center aisle, so in a bus with a chassis frame, the ground clearance may not be too high. It also has drawbacks such as the fact that the frame on which the sub-engine is mounted is heavy, reducing stability.

In addition, in any of the above bus cooling systems, if a general diesel engine is used as the sub-engine, if the rotation speed is too low, the torque fluctuation range when each piston explodes becomes too large. Since the engine speed could not be lowered below about 1000 rpm, the sub-engine would be operated with more output than necessary even when the cooling load was small, making it impossible to precisely switch the cooling capacity. Moreover, there is a problem in that fuel is wasted and engine noise is loud even at low loads.

The present invention has been made in order to solve the above-mentioned problems.The purpose of the present invention is to avoid the above-mentioned problems when mounted under the floor of a vehicle, to have an excellent left and right weight balance, and to reduce the cooling load. To provide a cooling device for a vehicle that can perform detailed operation according to the air conditioner, has a low noise level during low cooling loads, and can save fuel.

According to the present invention, in order to achieve the above object, at least two sub-engines that drive the compressor of the refrigerant circuit are installed under the floor, and the sub-engines are separated on one side and the other side with respect to the longitudinal centerline of the vehicle body. and install it.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, cooling units A ₁ and A ₂ are mounted under the floor of a bus 1 on one side and the other side of the longitudinal centerline O--O of the vehicle body. As shown in Fig. 2, the bus 1 has high floor plates 2, 2 on the left and right sides and a low floor plate 3 in the central aisle.
Cooling units A ₁ and A ₂ are provided below.

Figure 3 shows the cooling unit with the floorboard removed.
A partial cross-sectional plan view of A ₁ and A ₂ is shown, and FIG. 4 is a partial cross-sectional end view as seen in the bus traveling direction with some parts omitted. In the illustrated embodiment, the left and right cooling units A ₁ and A ₂ have the same structure, so only one cooling unit A ₁ will be described.

The cooling unit A ₁ has a frame 4, on which a small sub-engine 5 is fixed with anti-vibration rubber (not shown), and a compressor 7 is attached to the sub-engine 5. The compressor 7 is driven by the sub-engine 5 through a transmission mechanism 8 consisting of a pulley and a belt. A blower fan 9 is further connected to the sub-engine 5.

A sub-engine cooling radiator 11 and a condenser 12 of a refrigerant circuit of the refrigerator are supported on the frame 4 facing the blower fan 9 . The radiator 11 can be placed on top of the capacitor 12, for example. An outside air intake port 14 is provided in the bus body 13 so as to face the radiator 11 and the condenser 12, and a blower fan 9
As a result of the operation, outside air is sent under the floor via the outside air intake 14, the radiator 11, and the condenser 12, while being guided by the casing 16. This outside air cools the radiator 11, condenser 12, sub-engine 5, and compressor 7.

An evaporator 18 of the refrigerant circuit is adjacent to the radiator 11 and the condenser 12 in the longitudinal direction of the vehicle body.
is installed on frame 4. The evaporator 18 is provided within a casing 19, and an in-vehicle air intake port 22 is provided on the upper surface of the casing for sucking in in-vehicle air from an opening 20 in the floor plate 2 through a duct 21. Further, the intake side of a blower 24 is connected to the inner surface of the casing 19, and the blower 24 is operated by the sub-engine 5.
It is driven by a transmission mechanism 25 consisting of a pulley and a belt.

The outlet of the blower 24 has a connection tube 25, and a blower duct 27 is connected to this connection port as shown in FIG. 5, and a rising duct 28 shown in FIG. 2 is further connected to this duct 27. , its terminal is connected to a cold air outlet 29 on the ceiling. Therefore, by operating the blower 24, the air inside the vehicle is sucked in through the opening 20, cooled by the evaporator 18, passed through the tacts 27 and 28, and blown into the vehicle interior through the outlet 29, thereby performing cooling.

As is well known, the compressor 7, condenser 12, and evaporator 18 constitute a refrigeration cycle together with a liquid tank, an expansion valve, etc. (not shown).

A suitable electromagnetic clutch 31 is connected to the input shaft of the compressor 7.
(not shown) is preferably provided to cut off the input to the compressor 7. In addition, the sub-engine 5 is provided with a rotation speed control device (not shown), and
It is preferable to enable a low rotational speed switching operation.

The low floor plate 3 is supported by a chassis 33 as shown in FIG.

Regarding the operation of the vehicle cooling system described above, when the temperature inside the vehicle is high and the cooling load is large, both the cooling units A ₁ and A ₂ are operated at high speed. That is, both sub-engines 5, 5 are switched to the high rotation speed side and operated. This allows the cooling device to perform at its maximum capacity.

When the cooling load decreases, the cooling capacity can be reduced by switching one of the cooling units A ₁ and A ₂ to low-speed operation.

Furthermore, when the cooling load decreases, both cooling units A ₁ and A ₂ are put into low-speed operation.

If the cooling load decreases further,
One engine 5 of the cooling units A ₁ and A ₂ is stopped, and only one of the cooling units is operated.

On the other hand, when only air blowing is performed without cooling, the power to the compressors 7 of both cooling units is cut off by disengaging the electromagnetic clutches 31. As a result, the refrigeration cycle is stopped and only the blower 24 is operated.

In this embodiment, since there is no need for a duct that crosses the vehicle body, a large space is created under the floor in the center of the bus, and the maintainability under the floor is very good.

In the example shown in FIG. 5, a dedicated cold air duct 27 is provided for each cooling unit A ₁ , A ₂ , but instead of this, as shown in _FIG . Connect the common duct 33 to _{the tube} 25
Alternatively, a pair of switching dampers 34, 34 may be provided. By switching the dampers 34, 34 to the solid line position, both cooling units
The cold air from A ₁ and A ₂ is sent into the vehicle interior independently of each other, but one cooling unit is stopped, the damper 34 belonging to that cooling unit is switched to the imaginary line position, and the damper 34 belonging to the other cooling unit is moved to the dotted line position. By switching to the position, the cold air from the other operating cooling unit is routed to the ducts 28 on both sides.
(Figure 2).

The examples in Figures 3 and 4 are for cooling units.
A ₁ and A ₂ are supported by separate frames 4,
The frames 4, 4 may be made into a common unit, and independent cooling unit equipment may be arranged therein.

On the other hand, in the examples shown in Figures 3 and 4, equal cooling units A ₁ and A ₂ are installed on the left and right sides of the center line O-O, but both cooling units do not have to be equal, and , the number of cooling units on either side of the center line OO may be three or more. In any case, the sub-engine 5 of the cooling unit is
- It is important that they are mounted separately on the left and right sides of the O. The number of compressors 7 driven by the sub-engines 5 on each side of the center line OO may be one or more. Furthermore, each refrigerant circuit does not need to be completely independent; for example, a dryer or a compressor may be shared.

FIG. 7 shows an example in which cooling units A ₁ and A ₂ are mounted on the same frame 4a and are arranged in opposite directions in the longitudinal direction of the vehicle body. In this example, the left cooling unit
A ₁ is the same as the cooling unit A ₁ shown in FIG. 3, but since the arrangement of the cooling unit A ₂ on the right side is reversed, the cooling air is transferred from the connecting tube 25a to the connecting tube by the connecting duct 36 that turns into a U-shape. It is designed to lead to the position 25b. The connection on the downstream side of the connecting tubes 25, 25b can be made in the same manner as shown in FIG. 5 or 6.

As described above with respect to the embodiments, according to the vehicle cooling system of the present invention, as a result of providing the sub-engines separately on one side and the other side with respect to the longitudinal centerline of the vehicle body, the left-right balance of the vehicle body is improved. Not only is it better, but it also allows the use of smaller sub-engines, which eliminates the need for the sub-engines to protrude between the chassis seats like in the past, making it possible to install an air-conditioning system in buses that use this area as the center passage. becomes. Also, by having the sub-engines on each side, there is no need to pass the propeller shaft from one side to the other, making it possible to mount the cooling system on buses with chassis of any height.

As a result of separating the sub-engine into the left and right parts in this way, the cooling unit can also be separated into the left and right parts, so two independent cooling systems can be used.
As more than one cooling system is installed, it is now possible to operate all cooling systems simultaneously or selectively operate only some cooling systems, making it possible to precisely switch the cooling capacity. Even if the system breaks down, it becomes possible to use another system for cooling, and the ability to attach and detach each cooling system improves maintainability.

In addition, since multiple cooling systems can be installed, the cooling capacity per system is smaller than before, and the amount of heat released by the heat exchanger is lower than that of conventional systems.
Since the diameter of the blower fan can be reduced to about 1/2, the area of the blower fan can be reduced to about 1/2.
4, its weight can be reduced, and noise can also be reduced.

Furthermore, since a small cooling load can be handled by operating a part of the cooling system, fuel can be saved compared to the conventional case, and engine noise at a small load can be reduced.

Note that the principles of the present invention can also be applied to vehicles other than buses.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the positional relationship between the bus body and the cooling unit, FIG. 2 is a longitudinal sectional view of the bus, FIG. 3 is a partially sectional plan view showing the main parts of the vehicle cooling system of the present invention, and FIG. 5 is a plan view showing how to connect the cold air duct, FIG. 6 is a diagram showing a modification of FIG. 5, and FIG. 7 is a diagram showing another example of the vehicle cooling system of the present invention. FIG. 3 is a partially sectional plan view showing the main part of the example. DESCRIPTION OF SYMBOLS 1... Bus, 2, 3... Floorboard, A ₁ , A ₂ ... Cooling unit, 4, 4a... Cooling unit frame, 5... Sub-engine, 7... Compressor, 11... Sub-engine cooling radiator, 12... Condenser, 13 ...Vehicle body, 14...Outside air intake, 18...Evaporator, 2
4...Blower, 27, 28, 33...Cold air duct, 2
9... Cold air outlet, 31... Electromagnetic clutch, 34... Damper, 36... Duct.

Claims (1)

[Scope of Claims] 1. A refrigerator having a refrigerant circuit consisting of a compressor, a condenser, a liquid tank, an expansion valve, an evaporator, etc., a blowing system that brings air into contact with the evaporator and sends it into the vehicle as cooling air, and a compressor. A vehicle cooling system comprising at least two sub-engines installed under the floor for driving the vehicle, and these sub-engines are mounted separately on one side and the other side with respect to the longitudinal centerline of the vehicle body. Device. 2 The refrigerant circuits of the refrigerators driven by the sub-engine on one side of the vehicle body are arranged on the same side, and the refrigerant circuits of the refrigerators driven by the sub-engine on the other side of the vehicle body are arranged on the same side. A vehicle cooling device according to claim 1, which is arranged on the side. 3. A vehicle according to claim 2, in which a cooling unit consisting of a sub-engine and a refrigerant circuit on one side of the vehicle body and a cooling unit consisting of a sub-engine and a refrigerant circuit on the other side of the vehicle body are mounted on independent frames, respectively. cooling equipment. 4. A vehicle air conditioner according to claim 2, in which a cooling unit consisting of a sub-engine and a refrigerant circuit on one side of the vehicle body and a cooling unit consisting of a sub-engine and a refrigerant circuit on the other side of the vehicle body are mounted on the same frame. Device. 5 The blower system that brings air into contact with the evaporator of the cooling unit consisting of the sub-engine and refrigerant circuit on one side of the vehicle body and the blower system that brings air into contact with the evaporator of the cooling unit consisting of the sub-engine and refrigerant circuit on the other side of the vehicle body are independent. A vehicle cooling device according to claim 2, which is provided with: 6. A ventilation system that brings air into contact with the evaporator of the cooling unit consisting of a sub-engine and refrigerant circuit on one side of the vehicle body, and a ventilation system that brings air into contact with the evaporator of the cooling unit consisting of the sub-engine and refrigerant circuit on the other side of the vehicle body, downstream of the evaporator. The evaporator downstream side of one blowing system is closed and the downstream side of the other evaporator is connected to the outlet of both blowing systems, and the downstream side of the evaporator of both blowing systems is open. 3. The vehicle cooling system according to claim 2, further comprising a damper device provided in the vicinity of the common duct, which is switchable between a damper device and a position where communication between both air blowing systems is interrupted.